Masses of such slopes consist of soil layers having non-uniform physico-mechanical properties characterized by complicated engineering geology and hydrogeological conditions are seriously aggravated in seismically active areas where this invention can also be successfully used.
All methods presently used for the development of territories complicated by ravines or hollows are expensive and require considerable amount of materials and labour effort since the structures of up-to-date retainment and landslide protection installations, which are part of a development complex, are mainly used to retain in equilibrium masses of fill soil used for backfilling of a ravine or hollow or to stabilize landslide phenomena and are practically not used as foundations for erecting buildings or installations thereupon.
At the same time, there is an evergrowing shortage of land with flat terrain whose lots are primarily used for agriculture and recreation.
The trends in the development of territories complicated by ravines or hollows show that construction is usually carried out by erecting massive retainment landslide protection installations with the subsequent backfilling of a ravine or hollow.
Retaining wall is one of the widely used retainment structures. There is a great variety of designs of retaining walls which are made of various materials. In most cases, the retaining walls are used for levelling purposes, i.e. the retaining walls back-up comparatively small soil masses from sliding. However, in some cases the retaining walls can be also used under considerably landslide pressures. A crib-type retaining wall is considered to be one of the most economical designs among the structures of this type which are capable of taking-up a considerable horizontal force.
A lattice-type design consisting of vertical reinforced concrete and metal members extending through landslide soils and secured in stable soil layers is considered more rational a design than the retaining walls. The soil between these members performs together with them forming a retainment installation. Among such structures there are piles (precast piles, cast-in-place piles, filled-in piles).
The above mentioned structures are generally loaded by bending. If similar members do not extend through the entire landslide mass but extend only in a sliding plane area, such constructions will be generally loaded with shear.
In some cases it may be preferable to use landslide protection structures such as so-called anchor-and-stays installations. In this case, a slab or a lattice-type structure is placed on the slope surface and secured to stable soil layers by means of flexible tie rods cutting through the body of landslide soils.
To protect embankments and excavations, buttress structures are used which extend along a slope and are disposed at some interval from each other across the slope. The soil between the buttresses form vaults which prevent the landslide mass from pressing through. The buttresses are made of stone, concrete and reinforced concrete.
Also known in the art is a landslide protection structure made in the form of piles which are rigidly interconnected by a pilework bearing against massive abutments. This structure substantially improves static performance of piles and reduces consumption of materials.
Known in the art is a landslide protection structure in which active and landslide soil pressure is taken-up by a combined retaining wall having reinforced concrete arch structures. The retaining wall is in the form of a prism of a stone of crystalline rocks on the outer slope of which there are horizontal reinforced concrete arches disposed at different height and serving to take-up an excessive pressure exerted on the wall. The arches bear against reinforced concrete foundations made in semirock or rock soils of the ravine sides. A disadvantage of this design resides in considerable consumption of materials and high cost caused by the fact that the retaining wall takes-up a landslide pressure only by virtue of friction between the wall and soil bedrocks so that the retaining wall should be of a considerable cross-sectional area. To enhance a load-bearing capacity of the retaining wall under slip, it is necessary that its outer slope be reinforced with reinforced concrete arches. Furthermore, a substantial disadvantage of the retaining wall design resides in underdevelopment of territories complicated by ravines because when this design is utilized it is only possible to backfill the ravine with soil which connot be used as a base for a building or installation because of large non-uniform settlements which occur in backfilling. A lot formed upon the ravine backfilling is used not for erection of buildings but for making sporting grounds, parks, etc., the possibility of using this landslide protection structure as foundation of a building or installation being out of the question.
Known in the art are foundations of buildings or installations erected across ravines extending along slopes.
Generally such foundations consist of vertical longitudinal and transverse walls. When such foundations are erected in ravines, the outer longitudinal wall facing towards a higher ravine point is either in contact with the soil of the ravine backfilling and takesup the horizontal pressure of the backfilling mass or is not in contact with this backfilling.
In the latter case, slope retainment structures are erected which are in the form of retaining walls located in front of the outer wall of the foundation which faces towards a higher ravine point.
In both cases, the soils of the ravine slopes are under the action of the inclined component not only of the weight of the soil of the ravine backfilling but also of the inclined component of the foundation weight and the weight of a buiding erected thereupon.
A substantial disadvantage of such foundations is a considerable shearing action exerted upon weak soils of the ravine bottom which may result in a loss of stability of the ravine bottom soils under the building. Because of this, in designing buildings on such slopes the ravine backfilling weight acting upon the foundation is taken into account. In order to take-up additional shearing loads acting upon the foundation, its walls are reinforced or additional retaining walls are erected which results in a considerably higher amount of materials (concrete, steel) required for erection of a foundation and makes it much more expensive.
The present invention is based on the problem of providing such a foundation of a building or installation erected across a ravine extending along a slope whose design would make it possible to take-up loads caused by landslide pressure while taking-up loads from a building or installation.